It is an electronic flash strobe flashtube (perhaps missing the protective outer glass dome) that was made by Sylvania, GE, and others, usually known as a FT-120 or a FT-152 and was a 200 watt second flashtube.

The all silver contact in the middle that loops around the glass tube leads down to the pin that connects to the trigger transformer that fires the flashtube, and on the left and right side is the Anode (Positive) and Cathode (Negative).

However without being able to see the base of the flashtube for the corresponding pin numbers, I can't tell from the photo which one is the Anode and which is the Cathode whereas the trigger transformer is quite obvious.

Often the flashtube would have it's model number stamped on either the top of the protective outer glass dome or on the side of the protective outer glass dome down near the base.

Looking closely at the metal band on the left hand side where the glass tube ends, I can make out what appears to be "02" which leads me to believe it is the same flashtube as the GE FT-120GC (again lacking the protective outer glass dome makes it difficult to positively identify it), and it should fire using a Globe Strob 250 or a Globe Strob 500.

The reason for the confusion with the Anode and the Cathode is that a flashtube that will fire in a Globe Strob 250 and Globe Strob 500 has the pins wired differently from perhaps a flashtube that will fire in another brand of strobe.

The Mighty Light Speedlight comes to mind as a flashtube made for the Mighty Light Speedlight has Pin 1 of the flashtube connecting to the Trigger Transformer circuit, Pin 2 connecting to the Anode (Positive) circuit, Pin 3 connecting to the Cathode (Negative) circuit, with Pin 4 not being used at all.

Whereas a flashtube made for the Globe Strob 250 and Globe Strob 500 has Pin 1 of the flashtube not being used at all, Pin 2 connecting to the Anode (Positive) circuit and Pin 3 connecting to the Trigger Transformer circuit and Pin 4 connecting to the Cathode (Negative) circuit.